I am trying to configure streams for replicating table from oracle db1 to db2. db1 is in the host1 with services db1, db2 is in the host2 with services db2. host1 member of domain xxx.com, host2 is domain controller with domain name yyy.com

I look at the job with server manager, the jobs failed. Then I check the database link, and try to query. Error ocured as:
ORA-12638: Credential retrieval failed

I tried to changes services in tnsnames.ora but not solved.
What should i do?